The present invention relates generally to an electrical connector for low current devices, such as cord terminating and connecting plugs for telephones and the like. More particularly, it is concerned with a new and improved one-piece modular plug for terminating multi-wire telephone cords.
Modular type terminal plugs of the type described are now being used extensively in the telephone industry as a rapid and easy means of providing the requisite interconnection between a base and hand set of a telephone, between the base and wall terminal block of such units and between wall blocks and other components of the system. The plugs are mounted on both ends of a length of multi-wire telephone cordage and are operatively secured thereto. The plugs may then be cooperatively received within receptacles or jacks in the various telephone units to accurately align the contacts connected to the wires in the plug with mating terminals within the various components of the system. A typical example of a connecting plug used in this manner can be found in the Hardesty U.S. Pat. No. 3,860,316 and other examples can be found in the patents mentioned therein. Although many of these plugs utilize two or more separate plug housing portions that are bonded together at the time of assembly, the aforementioned Hardesty patent discloses the advantages associated with making and using a one-piece modular connector. Accordingly, the disclosure therein is incorporated herein by reference.
In the Hardesty structure thin blade-like contacts or terminals having sharply pointed tangs are mounted within the dielectric housing of the connector in a side by side array with the pointed tangs driven through the tinsel or stranded core of each wire in the telephone cord for making a suitable electrical connection. However, if a tang is slightly bent it can completely miss the wire core or undesirably shear a portion or all of its tinsel core. As a result, problems can be experienced in maintaining the desired and necessary electrical continuity between the connected units. Additionally, since the pointed tangs preferably pierce the wire in such a way that the tang is aligned along the axial length of the wire. There is the possibility that the wire could be pulled through the tang and completely out of the plug during use. This can be a problem particularly where flat telephone cord is employed and the jacket of the cord is not firmly anchored within the plug.
Additionally, regulations and codes frequently require that the individual wires, particularly solid wires within the telephone cord must be specially treated, such as with a teflon insulation or coating in order to permit use of the cord within certain areas of a building. Unfortunately, such treatments substantially increase the cost of the telephone installation. Accordingly, the industry has been seeking all available means of lowering the cost of the remaining components, such as the terminal plugs, so as to reduce the entire cost of the installation while complying with the various codes and regulations.
The present invention advantageously provides a connector of the type described that positively locks the individual wires in place within the connector at each terminal making it virtually impossible to separate the cord from the connector, even when the jacket of the cord or the insulative covering on the wire is not firmly anchored. This is achieved in an economical fashion while eliminating the disadvantages associated with the pointed tangs of the terminals. At the same time there is provided both a positive electrical connection between the terminal and the wire core and a secure mechanical interlock between the terminal, the wire and the housing of the connector plug.
Other features and advantages will be in part obvious and in part pointed out more in detail hereinafter.
In accordance with the present invention, these advantages have been achieved by providing an improved electrical connector for terminating a low current multi-wire telephone cord or the like. The connector comprises a one piece dielectric housing having a cord receiving aperture with a plurality of terminal receiving slots extending between the aperture and a first or top exterior surface of the connector. The connector includes a recess operatively associated with the slots and extending from the aperture toward the exterior surface of the connector opposite the first or top exterior surface. Individual terminal blades of simplified configuration are positioned within the slots and have a wire contact portion adapted to pass through the longitudinal plane of the aperture into the recess. As the terminals are pressed into the housing for making electrical contact with the wires of the cord, they engage the wires of the cord and bend the wires out of the plane of the aperture and into the recess while simultaneously providing the requisite electrical contact.
The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth in the detailed disclosure.